This application claims the priority of German application DE 199 29 943.9, filed in Germany on Jun. 29, 1999, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a method and apparatus for determining the failure probability of a data network.
A signal level control method for optical conductor transmission paths is described in German Patent Document DE 19538753 A1. At least two optical conductor transmission paths in an optical data network are joined together via an optical coupler to form a multichannel system. The levels of optical signals vary as between the transmission paths, and differ in the different network sections, dependent on various factors. In particular, the optical components present in the different path sections attenuate the light level. Optical couplers are used to join the optical conductor transmission paths together. In order to match the different levels for this purpose, at least one automatically acting optical level controller is provided in each of the optical conductor transmission paths, and automatically adapts the level. A controllable optical attenuating element is proposed, for example, as the level controller.
A disadvantage of this type of data network is that, although the signal levels are equalized in order to join them together, level limit violations can nevertheless occur at the receiver, and can lead to failure of the data network. For example, the sensitivity of the receiver may be undershot or the receiver may be overdriven due to a receiver-dependent light level being undershot or overshot. Moreover, the optimum dimensioning of the data network is not disclosed.
One object of the invention is to facilitate the design and dimensioning of optical data networks.
Another object of the invention is to improve the robustness of optical data networks.
These and other objects and advantages are achieved by the method and apparatus according to the invention in which the failure probability of a data network which has at least one transmitter, a transmission medium, components which attenuate and/or amplify the power, and at least one receiver, is determined by subdividing the data network into individual point-to-point connecting paths, and determining a failure probability separately for each connecting point. The total failure probability of the data network is then determined as the sum of the individual probabilities of the individual point-to-point connecting paths, minus the probability that two or more point-to-point connecting paths will fail simultaneously.
A major advantage of these refinements is that a failure probability can be determined for the data network even when such data networks are being designed and dimensioned. This allows optimum design of the data network, in particular with regard to the insertion of attenuating and/or amplifying components. The data network can be optimized even at the planning stage so that, when it is brought into use, the probability of data network failures is minimized.